1. Field of the Invention
The present invention relates generally to an apparatus and method for detecting a fault in a digitizer, which inspect whether a fault has occurred in a digitizer provided in a touch panel and, more particularly, to an apparatus and method for detecting a fault in a digitizer, which can rapidly detect various faults or failures in conducting wires used as the channels of the digitizer within a short inspection time.
2. Description of the Related Art
Generally, a portable personal information processing device, such as a personal computer or a portable transfer device, performs a function of inputting text and/or processing graphics using various input devices such as a keyboard, a mouse, and a digitizer.
Further, in order to efficiently utilize various electronic devices, a touch panel for inputting signals in a display area of a display device without utilizing a remote control or the above-described input devices has been widely used. That is, such a touch panel is installed in the display area of an image display device, such as an electronic scheduler, a flat panel display device such as a Liquid Crystal Display (LCD) device, a plasma Display Panel (PDP), and an Electroluminescence (EL) device, or a Cathode Ray Tube (CRT), and is used to allow a user to select desired information while viewing the image display device.
Such touch panel types may be divided into a resistive type, a capacitive type, an electromagnetic induction type (EL type), etc. according to a method of sensing a touch.
Since the respective touch panel types have characteristics that exhibit problems differently in terms of signal amplification and resolution, as well as difficulty in design and processing technology, it is required to select a touch panel type enabling each advantage to be desirably utilized. For criteria for selection, not only optical characteristics, electrical characteristics, mechanical characteristics, anti-environmental characteristics and/or input characteristics, but also durability and economic efficiency must be taken into consideration.
A basic structure of a resistive touch panel is configured such that an upper transparent plate on which an upper electrode is formed and a lower transparent plate on which a lower electrode is formed are arranged close to each other on opposite surfaces so that a predetermined space is formed between the plates by a spacer. Therefore, the resistive touch panel is configured such that when any one point on the surface of the upper plate is touched by a predetermined input means such as a pen or a finger, the upper electrode formed on the upper plate and the lower electrode formed on the lower plate are electrically connected, and such that an output voltage changes due to the resistance at the point, the changed voltage is read, and then a control device detects location coordinates depending on a change in potential difference.
A basic structure of a capacitive touch panel is configured such that a matrix-type touch key array in which touch keys correspond to intersections of driving electrodes and sensing electrodes is provided on a single substrate. In the capacitive touch panel, if a drive signal is applied to a driving electrode, an output is determined by measuring a variation transferred to a sensing electrode in response to a variation in the drive signal depending on the degree of the capacitive coupling of the drive signal to the sensing electrode. Accordingly, at the intersection of a driving electrode and a sensing electrode indicating a given key, the degree of capacitive coupling between the driving electrode and the sensing electrode is determined depending on whether objects are present near the intersection. Therefore, the capacitive type is a scheme in which, when a finger or a conductive pen touches the touch key array, such an object changes the pattern of an electrical field between the driving electrode and the sensing electrode, thus detecting the location coordinates of the object.
A digitizer is a sensor for recognizing the location coordinates of a touch point which a predetermined input means such as a pen or a finger touches in the touch panel. In the digitizer, since conducting wires are configured in a grid shape, there is a problem in that internal failures or faults, such as irregular intervals between conducting wires, disconnection or short-circuit of the conducting wires, bending of the conducting wires, and/or non-uniform thickness of the conducting wires, occur in a manufacturing procedure.